


Baby Oh Baby

by thugboyfriendnagisa



Category: Haikyuu!!
Genre: Alpha/Beta/Omega Dynamics, Domestic, Domestic Fluff, M/M, Mpreg, Parenthood, their BUTT CHILD
Language: English
Status: Completed
Published: 2015-01-06
Updated: 2015-01-06
Packaged: 2018-03-06 08:15:28
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,823
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3127493
Author URL: https://archiveofourown.org/users/thugboyfriendnagisa/pseuds/thugboyfriendnagisa
Summary: <blockquote class="userstuff">
              <p>"It had been officially six weeks since Hinata and Kageyama had conceived, and the pregnancy book that Hinata had started reading had said that six weeks was the perfect time to tell your family you’re expecting. It had also said that their baby was about the size of a pomegranate seed now, which wow what the fuck how could a baby be the size of a pomegranate seed?"</p><p>In which Hinata and Kageyama have a baby together.</p>
            </blockquote>





	Baby Oh Baby

When Hinata woke up, he felt achy, but not as hot and bothered as he had been feeling for the past few days.

 _Guess our heat cycle is over_ , he thought, sitting up and stretching, feeling his back crack. He pushed back the covers, shivering at the cold morning air and making his way to the bathroom to clean up.

While he was going to the bathroom, he kept glancing at the little box sitting on the shelf above the toilet.

“Nope,” he muttered to himself, “I promised Kageyama I would wait ‘till he was awake.”

He glared at the box, mocking him, the little devil whispering into his ear that he should just _take one now_ , _Kageyama could just find out later_ , and _it takes three minutes to get the results anyway, Kageyama would be awake in three minutes._

With all the willpower he could muster, he turned away from the box and stepped into the shower to clean himself up.

-x-

“Good morning!” Hinata greeted, Kageyama giving his greetings around a yawn.

Hinata bumped their foreheads together before giving Kageyama’s chin an affection nip, then pressing their lips together. Kageyama hummed in approval.

“Are you gonna shower?” Hinata asked, and Kageyama nodded, stretching with a grunt. “Want me to make breakfast?”

“Sure. Don’t burn the house down.” Kageyama replied, and Hinata rolled his eyes, slapping Kageyama on the butt as they parted ways.

-x-

Hinata set the little plastic stick on the counter of the bathroom and set the timer on his phone, immediately exiting the bathroom and climbing into Kageyama’s lap.

“I was reading,” Kageyama huffed, adjusting himself to accommodate the omega in his lap and see the magazine he was reading.

Hinata didn’t reply, only rested his head on Kageyama’s chest, watching the timer count down the minutes before the test would reveal the results. Kageyama would stop reading every few seconds to comfortingly nuzzle his nose into Hinata’s hair, and Hinata would cuddle into Kageyama’s neck, keeping his eyes on his phone.

When the timer beeped, the two of them stood up and made their way to the bathroom.

Hinata swallowed, making his way to the intimidating little stick and picking it up, taking a deep breath before turning it over to see the results.

“…Well?” Kageyama asked, his voice scratchy.

Hinata’s breath left him in a rush, his body sagging.

“…Negative.” He said softly, tossing the stick into the garbage. He walked straight into Kageyama’s arms, letting him rub his back and pepper kisses on his face and neck.

“Next time,” Kageyama promised, “Next time, okay? It’s okay.”

“Yeah,” Hinata choked out, his hands grabbing the back of Kageyama’s shirt as he sniffled wetly.

-x-

A few weeks after the negative test, Hinata started to feel…off.

“Morning,” Kageyama greeted him, “I made your favorite.”

Hinata looked to the table excitedly, his mouth watering at the thought of shoving tamago kake gohan in his face, but as soon as the smell of rice and eggs hit his nose, his face screwed up.

“Oh my God,” he muttered, plugging his nose, “Has this always smelled this _awful?_ ”

“What?” Kageyama asked, smelling the air, “Smells fine to me. Are you feeling alright?”

“No,” Hinata immediately replied, feeling his stomach churn, turning and rushing to the bathroom.

“Hinata?!” Kageyama grimaced when he heard the retching from the bathroom, getting his husband a glass of water.

“You alright?” he asked as soon as he reached the bathroom, Hinata hunched over the toilet bowl groaning pathetically.

“Yeah, I think so,” he whined, gratefully taking the glass of water after flushing the toilet.

“I guess that’s a no to tamago kake gohan for breakfast,” Kageyama muttered, wincing as Hinata started barfing again at the mere mention of the food.

Yes, things were indeed… _off_.

-x-

After the fourth morning of waking up and immediately rushing to the bathroom, Hinata knew something was wrong.

He wasn’t coming down with anything, because after vomiting for a majority of the morning, the queasiness usually went away in the afternoon, and Hinata could stomach light things like crackers or toast.

After emptying his stomach for the morning, he glanced up to the little box on the shelf again, furrowing his brow and standing on wobbly legs, shaking out the last little stick in the box. He frowned, rinsing his mouth out with mouthwash before drinking two glasses of water.

He peed on the stick, shaking it off and setting it face down on the counter, setting his timer and sitting on the toilet lid and waiting.

“You alright in there, Hinata?” Kageyama asked, knocking on the door.

“Yeah, I’m alright,” he replied, glaring at the little stick.

“You need anything?” Kageyama asked, and the timer on Hinata’s phone went off. “What was that?”

Hinata took a deep breath, standing up and reaching for the little stick. His hand hesitated, but he steeled his nerves and closed his eyes, picking up the stick.

When he opened them, he saw a little red plus.

“Hinata? Are you sure everything is alright?” Kageyama tried the door knob, twisting it and finding it unlocked. “Hinata?”

Hinata looked up, Kageyama looking at the little white stick in his hand in confusion.

“…Kageyama,” he breathed, holding the stick out to him with wide eyes and shaky hands.

Kageyama furrowed his brow, then took it, his eyes widening at what he saw.

“…Shouyou,” he whispered, looking back up at the shell shocked omega, “Does...Does this mean-?”

“I’m pregnant,” Hinata whispered, “Tobio, I’m _pregnant_.”

The little stick fell to the floor with a _clack_ , Kageyama rushing over to gather Hinata in his arms, both of them laughing and crying in joy.

-x-

“Okay, Shouyou, why did you invite all of us over for dinner?” his mother asked, giving him a suspicious look.

Hinata’s parents and Natsu were sitting on one side of the dining room table, Kageyama’s parents sitting on the other side.

“And why didn’t you eat any of it?” Natsu asked, “You usually eat like a pig.”

“Natsu-!” Hinata growled, then clenched his teeth, taking a calming breath and putting his smile back on. “I mean, what’s so wrong with inviting my parents and the in-laws over for dinner?”

“Nothing at all!” Kageyama’s mother piped up with a smile, “Especially when my little man made such a delicious dinner for everyone!” she reached over to pinch Kageyama’s cheek, Kageyama batting her hand away with a grumpy frown and red cheeks.

“Well, okay, I mean, we invited everyone over for a _reason_ ,” Hinata relented at his mother’s quizzical look.

It had been officially six weeks since Hinata and Kageyama had conceived, and the pregnancy book that Hinata had started reading had said that six weeks was the perfect time to tell your family you’re expecting. It had also said that their baby was about the size of a pomegranate seed now, which _wow_ what the _fuck_ how could a baby be the size of a _pomegranate seed?_

“What’s the reason, sport?” his father asked, and Hinata grinned, looking at Kageyama, who nodded.

“Weeeelllllll,” he grinned wider, throwing his arms out before announcing, “I’m pregnant!”

There was a beat of silence before Hinata and Kageyama’s mothers both shrieked in excitement, clambering out of their seats to kiss Hinata all over his face.

The parents kissed and congratulated the two of them, and Natsu sat at the table, continuing to eat her dinner.

“Natsu?” Hinata asked, “What’s wrong? I thought you would be excited?”

“Oh, I am,” she replied around a mouthful of beef, “But I just learned how alphas and omegas make babies in school, so…This is a little gross for me.”

-x-

Soon, Hinata’s belly began to grow and swell, and with every visit to the doctor and seeing the ultrasounds make Kageyama’s eyes widen and Hinata’s eyes overflow with tears.

“God, I just love them so much,” Hinata blubbered, looking at the ultrasound machine, “I love that little grapefruit sized baby that makes me have to pee every two minutes.”

Hinata had to deal with mood swings and cravings and the occasional nosebleed. So did Kageyama.

“Kageyamaaa,” he whined, “I want strawberry shortcake.”

“We don’t have any?” Kageyama asked, half interested as he read over the recent results from different volleyball matches on his laptop.

“No,” Hinata whimpered, “There’s no cookies either. Or pickles. There are no mozzarella sticks. Or jalapeno poppers. God, I want a quesadilla.”

“What the fuck?” Kageyama muttered to himself, closing his laptop and walking into the kitchen, where Hinata stood, looking inside their fridge forlornly. “Are you alright?”

Hinata burst out crying and Kageyama jerked back in shock.

“I want shortcake! I just want shortcake, Kageyama, is that so much to ask?!”

“Okay, okay! Jeez, I’ll go get you anything you want from the store, alright? Don’t cry about it!”

“I c-can’t stop crying!” Hinata wailed, wiping his eyes with his sleeves, “I-I’ll make you a l-list for the store, okay?”

“Alright,” Kageyama sighed, leaning against the door frame as Hinata grabbed a piece of paper and a pen, writing down his list, whimpering and sniveling the entire time.

Kageyama took the list from Hinata and kissed him goodbye, walking out the door, heaving a sigh of relief.

He spent his sweet, sweet time at the store, savoring every moment that he was away from Hinata’s crazy mood swings.

-x-

But Hinata wasn’t the only one susceptible to mood swings, it seemed.

Kageyama was feeling something, too. Especially when he and Hinata went out, he would feel extremely angry when someone bumped into Hinata or brushed him or looked at him.

They were going out for lunch with Yachi to discuss possible times for her to babysit if they needed her, and it was fine for a while, Kageyama only getting a little miffed when Yachi hugged Hinata in greeting, but he hugged her as well, everyone bumping their foreheads together.

“Ah, wow, you’re glowing, Hinata!” she said happily, Hinata beaming at her compliment.

“Am I?” he asked, and she nodded, grinning as well.

“Does it kick yet?” she asked, and Hinata hummed, shrugging.

“Not really, but kinda? Like the baby has moved around, but Kageyama hasn’t felt it.” Hinata explained and Yachi nodded.

“Um, well, could I…?” Yachi reached her hand out, and Hinata nodded, but both of them stopped cold when Kageyama grabbed her wrist and growled at her.

Yachi instinctively lowered her head with a yelp and a whine, Hinata crying out Kageyama’s name, and Kageyama’s eyes widened, letting her go quickly.

“I-I’m sorry! I’m sorry, Yachi, I don’t know-” he moved in to bump her forehead apologetically, and she whimpered, accepting it all the same.

“S-Sorry, Kageyama! I-I’m sorry, I-I forgot-”

“No, no, I should be sorry! I don’t know what came over me…”

“A-Alpha instincts!” Yachi stammered, “I-It’s just something that happens during omega pregnancy…You just get super protective in order to keep Hinata and the baby safe! S-So it was my fault! I should have realized…”

“N-No, it’s fine! Really! I’m sorry for hurting you…” Kageyama bumped their foreheads together again and Yachi giggled.

“C’mon, let’s eat! We’ll treat you, Yachi!” Hinata ushered both of them into the restaurant they were standing in front of, laughing nervously the whole way.

When they got home, Kageyama demanded that they scent mark right away, Hinata laughing at him as he rubbed against Hinata’s neck earnestly.

-x-

Time marched on, and Hinata’s belly grew, as well as their baby.

They revealed the sex to family and friends at the baby shower, Hinata’s grin threatening to split his face in half as he proudly carried a balloon into the backyard that exclaimed ‘It’s a boy!’ in blue print.

“What color should we paint their room?” Hinata asked, standing with Kageyama in the nursery, flipping through a paint color pallet.

“Uh, blue?” Kageyama asked.

“No, we can’t force gender roles on our baby so early!” Hinata cried, “What if our baby feels like it’s actually a girl and we surround them with all this boy stuff?!”

“Girls can like blue and boy stuff,” Kageyama argued, “Just like how boys can like pink and girl stuff. What color were you thinking?”

“Oh, I don’t know,” Hinata admitted, “I’ve been looking through this thing for a week now and I still can’t decide.”

“Well, let’s do this,” Kageyama said, taking the colors from Hinata to glance through, “Let’s narrow it down to three colors we really like, go buy them, and paint a swatch on the wall. Then pick the one we like best.”

“Great idea, Kageyama!” Hinata smiled, “See, I knew there was a reason I married you.”

“Uh huh,” Kageyama replied, flipping through the colors. “How about mint green?”

“Ooh, that one is nice,” Hinata flipped through, pointing to a light yellow color, “I really liked this one, too.”

The two of them wandered from the nursery to the living room, lounging on the couch and flipping through, making note of the colors they liked, then glancing through some sample carpets that Yamaguchi (conveniently an interior designer) had lent them.

-x-

They finally narrowed it down to ‘Mellow Yellow’, ‘Bonnet Blue’, and ‘Mint Green’, and settled on a nice cream colored carpet to match all three colors. They went to the store and bought a can of each of the paints, and supplies, and swatched the colors on the wall.

“I think I like the mint green a lot,” Hinata said, and Kageyama agreed.

They painted their nursery mint green, then they had the cream colored carpet laid down. They then called Yamaguchi over, and he helped them rearrange all the furniture they had gotten from their baby shower and the rest they purchased themselves.

“Yamaguchi and I will handle the moving,” Kageyama insisted, “You just relax, okay?”

“Ugh, fine,” Hinata griped, “But I’m only agreeing because my ankles really hurt…”

So Hinata rested on the couch, keeping his feet elevated, as Kageyama and Yamaguchi rearranged furniture for their nursery.

A couple hours later, Yamaguchi and Kageyama emerged, Yamaguchi grinning widely.

“Well?” Hinata asked, smiling and wriggling to stand up from the couch, “Well, how is it?!”

“My best work, if I do say so myself,” Yamaguchi boasted, “…Well, my best work for a nursery. Actually, the only work I’ve done for a nursery.”

“It looks really nice,” Kageyama cut him off, “You’re gonna really like it.”

Hinata waddled towards the nursery, opening the door in excitement.

His breath left him in a rush when he saw everything nestled into place. The crib was pushed against the left wall, the changing station set up next to it and a toy box on the other side. On the opposite wall, toys and a bookshelf and a rocking chair were set up. There was a couple shelves with picture frames and statuettes they had received from the baby shower.

“Ah,” Hinata breathed out, then turned to Kageyama and Yamaguchi, grinning widely, “I love it! You did a great job, Yamaguchi!”

“It was no problem,” Yamaguchi reassured him, then glanced at his phone, “Ah, I gotta get going, I have an appointment with some couple in the area. See you guys later!”

Yamaguchi accepted Hinata’s grateful hug goodbye, waving to Kageyama as he left their house. Hinata marched straight back to the nursery, standing and admiring everything.

“The baby will be here soon,” Hinata said quietly, running his hands over his belly, “Soon we’ll be able to put him to sleep in his crib, and be able to play with him, and be able to rock him to sleep…”

“Yeah,” Kageyama replied, hugging Hinata from behind, his hands running over his belly as he nuzzled his nose into Hinata’s unruly locks.

“I’m a little scared,” Hinata admitted, “What if we mess up or something? Or if our baby isn’t happy?”

“All parents mess up,” Kageyama said softly, moving down to pepper soft kisses along Hinata’s neck, “And if our baby isn’t happy, we’ll do everything we can in order to make him happy. Don’t worry, okay? We’ll take great care of him. I know we will.”

“Okay,” Hinata smiled, leaning back against Kageyama, their hands settled on his stomach to feel the baby’s little kicks, “I trust you.”

-x-

Kageyama-Hinata Katsuro was born on a dreary night in late October. He had a mop of inky black hair and a grumpy frown, and Hinata wept because he was beautiful, his little Kageyama stink face and all.

“He looks just like you,” he blubbered to Kageyama, “Look, he’s even doing the same face you do when you’re cranky.” Kageyama’s face contorted into a frown, and Hinata grinned, “That one!”

“Shut up,” Kageyama muttered, leaning over the bed to observe the baby bundled up in Hinata’s arms, “He has your nose, though. And he has a bunch of cowlicks. Maybe he’ll have your eyes.”

“Maybe,” Hinata sniffed, rubbing his nose and running his finger over the bridge of Katsuro’s nose, watching with glee as his face scrunched up further. “God he’s so cute. I love him.”

“Me too,” Kageyama murmured, reaching over to run over his tiny fingers, which unfurled and tightly grasped it in a little fist, making Kageyama smile, “He’s perfect.”

-x-

“Kat-su-ro! Kat-su-chan!” Hinata chirped, grinning down at the little baby in the crib, who looked up at him with wide honey gold eyes, his pacifier snug in his mouth. “Katsu-chaaan, you’re so cute!” Katsuro stared at him, wriggling around his bed, and Hinata grinned wider. “Someone’s a little wiggle worm! A cute little wiggle worm!” Hinata reached down to lift Katsuro out of his crib, the baby quickly snuggling into his neck. “Let’s go see Daddy!”

Hinata carried Katsuro to the living room, where Kageyama was flipping through papers and listening to his agent on the other line.

“Yeah, yeah, so they rescheduled?” he asked, looking up and smiling softly at Hinata and Katsuro, “Okay. Okay. Just keep me updated on the date, yeah? Great. Thanks. I’ll talk to you later.” Kageyama hung up his phone and setting it on the coffee table. “Hey you two.”

“Hello!” Hinata smiled, Katsuro squirming around in his arms, “Look who’s a little wiggle worm!”

“Ah,” Kageyama reached out for Katsuro, who smiled around his pacifier, Kageyama laying him down on his lap and letting him grasp his fingers in his fists. “Are you a little wiggle worm today, mister?”

Katsuro giggled, squirming around in Kageyama’s lap.

“He is pretty squirmy, huh?” Kageyama smiled fondly, letting go of Katsuro’s hands so he could tickle his sides, making him squeal in delight.

Hinata watched on with adoration. It was still a little weird to see Kageyama baby-talk to their son, but it wasn’t unwelcome. He read that baby-talking to your child was important for mental development. Katsuro seemed to be enjoying himself, his early baby stink face loosening up to wide-eyed gazes and happy giggles. He still had the classic Kageyama resting bitch face, though, especially when he was trying to figure out a new toy or when his diaper needed to be changed.

“What?” Kageyama asked, “You have a gross mushy look on your face.”

“Because I _feel_ gross and mushy,” Hinata replied, moving closer to press a kiss to Kageyama’s cheek, “You two are adorable.”

Katsuro interrupted with a high pitched noise, his pacifier rolling out of his mouth. Kageyama caught it before it fell to the floor, and Hinata grinned at their son.

“What? What is it, Katsu-chan?” he leaned over to rub their noses together, “What is it baby, hm?”

Katsuro grabbed at Hinata’s hair, giggling happily as he tugged.

“Ow. Okay, ow-” Hinata picked him up out of Kageyama’s lap, leaning back and whining as he continued to pull at his hair. “Kageyama, help-!”

 “Oi, Katsuro, that’s not nice,” Kageyama said in between laughs, prying his little fists away from Hinata’s hair. He popped his pacifier back in his mouth, smiling as Katsuro stared up at him with doe eyes.

“I think we’re doing pretty well so far,” Hinata said, adjusting Katsuro so he was laying on his chest above his heart, his little eyelids drooping almost immediately.

“Yeah, but this is when it’s kind of easy,” Kageyama said, “All he does is eat, poop, and cry, in that order.”

“No, no, no! Bad Kageyama!” Hinata gave his arm a smack, “Katsuro is doing a lot right now! He’s growing up little by little and his brain is developing! Every time we talk to him, he’s forming connections between his little neurons!”

“Do you even know what a neuron is?” Kageyama retorted, pinching Hinata’s cheek.

“Yeah, I do! They’re the cells in your brain, moron!” Hinata snapped, reaching out to pinch Kageyama’s cheek in retaliation.

“You only know that because you’ve been reading those stupid parenting books all the damn time!”

“Don’t swear in front of the baby!”

“He doesn’t- Ow! Watch it, dumba-butt! Dumb butt!”

The two of them stopped in their squabbling when Katsuro giggled loudly in delight. They stared at him before glancing at each other and bursting out laughing.

“Ooh, you like that don’t you?” Hinata cooed, tickling his stomach and grinning wider when Katsuro squirmed and laughed harder, “You like it when your daddies fight, hm?”

“Someone thinks it’s funny when his daddies fight about neurons, hm?” Kageyama added, leaning over to rub his nose against Katsuro’s, grunting in pain when his tiny hands latched onto his hair. “Ow, dude-“

“Did you just call our son ‘dude’?” Hinata asked with a snort, helping pry Katsuro’s grabby hands off of Kageyama’s hair.

“Whatever it’s not-mmph.” Kageyama was cut off by Hinata pressing their lips together in a short, soft kiss, blinking at him when he pulled away.

“Love you,” Hinata murmured, smiling when Kageyama kissed his cheek in return.

“Love you, too.”

“But I love you most of all, Katsu-chan!” Hinata crooned, leaning down to press kisses all over Katsuro’s face, making him squeal in delight.

“Hey, I love him more!”

“No you don’t, you didn’t carry him inside you for nine months!”

“I can still love him more despite that! I helped create him and made sure he was safe when he was inside you-“

“That is complete bullsh-bull crap and you know it. You can’t possibly love him more than I do-“

They were cut off again by Katsuro’s delighted laughter, his pacifier falling onto his chest as he giggled and squealed, thrashing about in Hinata’s arms. They stared at him in wonder, then looked at each other, smiling.

“I might have carried him inside me but,” Hinata looked back down at Katsuro, smiling fondly, “Every time he does that, it’s like falling in love all over again.”

“Yeah,” Kageyama agreed, resting his head on Hinata’s shoulders to stare down at Katsuro, his golden honey eyes and messy black hair and chubby cheeks, “Every single time he does that.”

**Author's Note:**

> (ignore that shitty title omfg)
> 
> if you told 14 year old me that i would be writing an mpreg fic about a couple that i have become too emotionally invested in at 21 years old, 14 year old me would have laughed in your face then probably say something offensive
> 
> man i did a lot of research for this? i was like googling a bunch of stuff about pregnancy and babies and i just got done learning about childhood development in one of my social work classes and diddly dang babies do a lot of work in the growing department. while you're telling them to get a job at like 12 weeks they're like making a bunch of synaptic connections in their little baby brains. PRETTY RAD FOR A USELESS SACK OF SHIT. (why do i want to have babies so badly i don't GET IT why lady parts W H Y DO YOU WANT THIS)
> 
> BUT THIS WAS FUN! and weird. Kageyama as a parent weirds me out. when i was writing about him interacting with the baby, i was like ".....kageyama does not seem like the type of person to do any of this stuff." still really interesting to think about and write! also lol @ the fact that they are married and still call each other kageyama and hinata. what the what.
> 
> anyway, let me know what you guys think!! never written anything like this before and i know mpreg is kind of hard to write and not a lot of people are on board with it, buT I MEAN HEY. lots of people wanted it. Mama Kim delivers.
> 
> thanks in advanced to all the comments and kudos!!! (*´・ｖ・)


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